1. Field of the Invention
This invention relates to a data processing system operable to perform a table lookup function and more particularly to a parallel processing system having multiple independent read only memory program storage areas which allow performing table lookup functions.
2. Prior Art
Conventional data processing systems perform the table lookup function utilizing, most frequently, a software tree. Beginning with a code value which specifies the table entry point address, a BIT of the code is tested to determine whether a conditional branch is to be taken. At the new location, whether it be the branch location or a fall-through location, the process is repeated, and so on, until the last bit is tested and the table value is located. Although the operation at each step in the iterative process is similar, dedicated instructions are normally required since branch instructions are generally fixed instructions. While it is possible to make the branch instruction modifiable, this requires the use of either a binary program counter or a binary to shift code conversion circuit to implement the table lookup function, either of these circuits requiring a large area of semiconductor wafer.